Portable mixer



FIG. 1 is a front and right-hand perspective view of a portable mixer showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a right-hand side elevational view thereof;

FIG. 4 is a left-hand side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a front elevational view thereof; and,

FIG. 7, is a rear elevational view thereof. 

The ornamental design for a portable mixer, as shown and described. 